153 lines
3.6 KiB
C
153 lines
3.6 KiB
C
/*
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* Copyright (C) 2004-2006 Atmel Corporation
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/dma-mapping.h>
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#include <linux/gfp.h>
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#include <linux/export.h>
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#include <asm/addrspace.h>
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#include <asm/cacheflush.h>
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void dma_cache_sync(struct device *dev, void *vaddr, size_t size, int direction)
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{
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/*
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* No need to sync an uncached area
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*/
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if (PXSEG(vaddr) == P2SEG)
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return;
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switch (direction) {
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case DMA_FROM_DEVICE: /* invalidate only */
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invalidate_dcache_region(vaddr, size);
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break;
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case DMA_TO_DEVICE: /* writeback only */
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clean_dcache_region(vaddr, size);
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break;
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case DMA_BIDIRECTIONAL: /* writeback and invalidate */
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flush_dcache_region(vaddr, size);
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break;
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default:
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BUG();
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}
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}
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EXPORT_SYMBOL(dma_cache_sync);
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static struct page *__dma_alloc(struct device *dev, size_t size,
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dma_addr_t *handle, gfp_t gfp)
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{
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struct page *page, *free, *end;
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int order;
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/* Following is a work-around (a.k.a. hack) to prevent pages
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* with __GFP_COMP being passed to split_page() which cannot
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* handle them. The real problem is that this flag probably
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* should be 0 on AVR32 as it is not supported on this
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* platform--see CONFIG_HUGETLB_PAGE. */
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gfp &= ~(__GFP_COMP);
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size = PAGE_ALIGN(size);
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order = get_order(size);
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page = alloc_pages(gfp, order);
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if (!page)
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return NULL;
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split_page(page, order);
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/*
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* When accessing physical memory with valid cache data, we
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* get a cache hit even if the virtual memory region is marked
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* as uncached.
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*
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* Since the memory is newly allocated, there is no point in
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* doing a writeback. If the previous owner cares, he should
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* have flushed the cache before releasing the memory.
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*/
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invalidate_dcache_region(phys_to_virt(page_to_phys(page)), size);
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*handle = page_to_bus(page);
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free = page + (size >> PAGE_SHIFT);
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end = page + (1 << order);
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/*
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* Free any unused pages
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*/
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while (free < end) {
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__free_page(free);
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free++;
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}
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return page;
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}
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static void __dma_free(struct device *dev, size_t size,
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struct page *page, dma_addr_t handle)
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{
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struct page *end = page + (PAGE_ALIGN(size) >> PAGE_SHIFT);
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while (page < end)
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__free_page(page++);
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}
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void *dma_alloc_coherent(struct device *dev, size_t size,
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dma_addr_t *handle, gfp_t gfp)
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{
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struct page *page;
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void *ret = NULL;
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page = __dma_alloc(dev, size, handle, gfp);
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if (page)
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ret = phys_to_uncached(page_to_phys(page));
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return ret;
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}
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EXPORT_SYMBOL(dma_alloc_coherent);
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void dma_free_coherent(struct device *dev, size_t size,
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void *cpu_addr, dma_addr_t handle)
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{
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void *addr = phys_to_cached(uncached_to_phys(cpu_addr));
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struct page *page;
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pr_debug("dma_free_coherent addr %p (phys %08lx) size %u\n",
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cpu_addr, (unsigned long)handle, (unsigned)size);
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BUG_ON(!virt_addr_valid(addr));
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page = virt_to_page(addr);
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__dma_free(dev, size, page, handle);
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}
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EXPORT_SYMBOL(dma_free_coherent);
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void *dma_alloc_writecombine(struct device *dev, size_t size,
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dma_addr_t *handle, gfp_t gfp)
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{
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struct page *page;
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dma_addr_t phys;
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page = __dma_alloc(dev, size, handle, gfp);
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if (!page)
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return NULL;
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phys = page_to_phys(page);
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*handle = phys;
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/* Now, map the page into P3 with write-combining turned on */
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return __ioremap(phys, size, _PAGE_BUFFER);
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}
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EXPORT_SYMBOL(dma_alloc_writecombine);
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void dma_free_writecombine(struct device *dev, size_t size,
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void *cpu_addr, dma_addr_t handle)
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{
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struct page *page;
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iounmap(cpu_addr);
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page = phys_to_page(handle);
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__dma_free(dev, size, page, handle);
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}
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EXPORT_SYMBOL(dma_free_writecombine);
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